Experimental Study On Ore Draw In A Model With Multiple Sub-levels And Ore Drawing Steps For Shachang Minebased On The Ory Of No-dilution Mining

Sublevel caving method is widely used in many iron mines around the worldfor underground mining because of advantages of simple technology, high degreeof mechanization, good safety, high output and easy management. But sublevelcaving method has a severe disadvantage of high dilution. This paper haveperformed a series of studies on drawing the ore with low dilution for Shachangiron mine based on theory of no-dilution mining.First of all, the experiment of ore drawing with low dilution is performed inlaboratory by using the physical model. In the model, there are five sublevels,each with three tunnels. In every single tunnel, ten ore drawing steps aredesigned. The experiment certificates that adherent residues are formed in theprogress of mining without dilution. This thesis preliminarily studies the role ofride residues, fringe residues and adherent residues in the progress of oredrawing with low dilution and the influence of three kinds of residues to differentsublevels and different steps in the same sublevel. The result proves that theprocedure of ore drawing with low dilution is a system, and it’s unwise to studythe interaction and mutual adjustment between steps and segments separately.Ride residues perform a leading role of adjustment in the process of ore drawing.Secondly, the experiment of cut-off grade ore drawing by six steps model iscarried out. The experiment proves that ore drawing with low dilution inShachang iron mine is feasible and confirms the roe drawing rules showed inprocess of experiment for ore drawing with low dilution. The result shows thatore drawing with low dilution can be achieved in Shachang iron mine and m utualadjustment among steps also exist in cut-off grade drawing because the form ofride residues are different which make the form of fringe rock difference.Thirdly, by drawing a line on the surface of the box dipping at75°, thephysical model box is used to study the ore drawing with low dilution forinclined ore body. Ore drawing with low dilution in inclined ore body is difficult,because the tilt line between rock and ore is unfavorable for the growth of theellipsoid. Part of ore in the tunnel is deliberately left to adjust the ore-rockcontact line horizontally. The result shows that ore drawing with low dilution in the case of dip angle of75°possible.Finally, comparison among the three groups of experimental results showsthat ore drawing with low dilution in Shachang iron mine is possible for both thecases of the straight ore body or inclined ore body. The economic benefits byusing this method in Shachang iron mine is considerate.